Machine fob boring dovetailed mortises



H. J. BETJEMAN MACHINE FOR BORING DOVETAILED MOR'TISES.

No. 7,807. Patented Dec. 3, 1850.

U TED STATES PA F ro I H. I. BETJEMANN, OF CINCINNATI, OHIO.

MACHINE FOR BORING DOVETAILED MORT'ISES.

To all whom it may concern Be it known that I, HENRY J. BETJE- MANN, ofCincinnati, Hamilton county, Ohio, have invented new and usefulImprovements in Machinery for the Manufacture of Joints for Attachingthe Rails to the Posts of Bedsteads.

The object of my invention is to construct a joint for bedsteads whichwithout the faults of the screw, is equally capable of closely huggingthe post, as the strain is placed upon it. It also admits more readilyof the use of a slot foundation, is durable and little subject to injuryand very expeditiously put together or taken asunder. These advantageousresults I accomplish by means of the following machinery for manufactureof the mortises which are to receive the tenons of the rail.

In the annexed drawings Figure 1 is a general perspective view of themachine one of the stops being detached. Fig. 2 represents the adjacentparts of a post and rail jointed on the proposed plan, A being the postand B the rail.

(a) is a bench or table of wood.

Z) Z) are a pair of stationary and 0 c a pair of shifting headstocks orstandards,

affording journal bearings for shafts cl cl which are armed at theirforends by ro-- tating cutters of form adapted to excavate the compoundreceding mortises (e c) with parallel external apertures or entrances (ff). Each cutter head consists of a truncated cone (g 9) whose sidesequal in longitudinal extension the depth desired for the flaring tenonand agree in their obliquity with its flare. This conic frustum is atits apex united by a cylindrical neck (h h) to the shaft. The end of thecutter is furnished with a bit (i i) nearly radial which scoops out thebottom (y' j) of the mortise, and its sides with a bit (70 7c) placedsomewhat spirally which carves out the bevel sides (6 c) of the mortise,and lastly the neck is armed with a small bit (Z Z) which goes to shapethe parallel edges of the mortise entrance. These cutter heads arerotated by bands passing around pulleys (m m) upon the shafts (d 0?).(n) is a shifting frame operable by a vibrating handle (2) whose lowerends are pivoted at (0) to the stationary portion. The latitudinalmotion imparted to the frame by the handle becomes (by guides hereafterdescribed) modified to a path of motion diverging sufliciently towardthe cutters to nick the binding faces of the mortises (which faces areformed by the conical sides of the cutter heads) gradually deeper withinthe post so as to cause the tenons (when the post and rail are puttogether) to be drawn slightly but powerfully within the posts as theyare pressed down along the mortises. The tenons are formed with a doubleobliquity both horizontal and Vertical in exact conformance with thebinding faces of the mortise.

The rotating cutter head in forming the mortise enters the postsufliciently to place the conical portion entirely within the postbefore the longitudinal motion is given to it so as to bring the neck orcylindrical portion into action, and thus give a square sink to theentrance of the aperture, and the cutting edge of the neck bit, movingin the same cylindrical path, throughout its entire length preserves theparallelism of the margins of the mortise entrance while the internalmortise varies in form and position throughout its length. This squareness and parallelism of the entrance margins preserves the post fromrending by lateral strain, and throws the pressure mainly outward, so asto bind the rail and post together, The peculiar obliquity of motion ofthe shifting frame (a) is derived from slots (39 p p p) in the frame,into each of which a pin 9) projects up from the bench. A forward motiontoward the cutters being impressed upon the frame or carriage, thelatter is by the longitudinal portion (2)) 0f the slot guided in a pathat right angles to the face of the post and by this means leads thecutter heads directly into the posts until the flaring portion isentirely imburied therein. A 1atitudinal motion of the frame, thencauses it to move under the control of one of the oblique grooves, so asat the same time that the mortise is continued longitudinally of thepost, it is also made slightly to recede and thus to remove the bearingfaces of the mortises farther from the face of the post as the cutterdescends therein, while the neck of the cutter being of the same sizethroughout, makes an external aperture that is of unvarying widththroughout its entire length below the part where the tenon enters.

A stop (1" 1") placed in the right hand oblique groove limits the playof the pin to the left hand ones and vice versa so that by thus closingone or other groove either a right or a left hand mortise may beobtained. One of the head stocks has straight lateral adjustabilitygiven to it;the apertures (s s) for the clamping bolts (t 5) beingextended laterally for that purpose. p

(a) is a tongue firmly affixed to the bench, and which overlapping theframe immedi ately in front of headstocks or standards, opposes anyarring or jumping upward of the frame. I g

(w) are slots upon the frame and serve to elevate the part out of theway of the tongue.

(v) are standards which serve both for a rest for the face of the post,and the arms (a?) being swung around in front and the notched clamps (y)being screwed down against the rear upper corner of the post,

the latter is thereby held fast to its proper position for the action ofthe cutter heads.

The operation of my machine is as followsTo cut the receding mortiseholes in the post it is secured to the carriage (n) by to advance bringsthe post in contact with the revolving cutters, which sink a hole of acylindrical form, to the depth required for that part of the mortise,the carriage is then advanced in a line at an angle say of 80 with itsformer direction not quite equivalent to right angle, which would carrythe cutter lengthwise of the post, and the n1or-' tise would then be asimple dovetail, and the tenon would enter and then traverse thedovetail without bringing the shoulder of the rail closer to the post atthe end of its range than it was at the beginning. The angle of itscourse being say about 80 with its former direction; as it progressesnearly lengthwise of the post it sinks deeper, and thus as the tenonrisentered and then by a blow or pressure caused to traverse the mortise itis drawn forcibly home until the shoulder of the rail closely hugs theface of the post, making a bug tight joint. The pins (9 g) are attachedto the bench on which the carriage slides and there projecting throughslots of the requisite length and direction in the carriage govern itsmotions as described. The slots in the carriage branch off right andleft with their former course so as to cut to the right or left asrequired; the stops (1' r) are placed in the slot which it is notdesired that the guide pin should traverse, so as to facilitate themanipulation of the machine which is so much more readily performed inthis way than by a method which requires the measure of distance by theeye; the retraction of the bit is performed by the reverse motion andthe integrity of the mortise is preserved by the guides and stopspreventing any action other than simple retraction of the bit by the wayit entered. It will be seen that the length of cut, the direction andthe degree of recession are regulated by-the slots in the carriage andby the guides and stops.

The tenons may be formed by two conical cutter heads of the flare andinterval apart corresponding to the tenon.

One, two or three tenons maybe made but -I prefer two as givingstability without unnecessary complication of parts. l Having thus fullydescribed the nature of :my invention what I claim therein as new anddesire to secure by Letters Patent is clamps (y 3 and the carriage beingcaused and arranged substantially as described, with 1. The rotatingcutters (g h z is Z) formed conical heads and cylindrical necks, incombination with a rest or movable table, for the reception andattachment of the bed post, the said table while being advanced towardthe cutters being conducted by suitable guides (79 p p) asdescribed-either upon the moving table or the stationary bench, in acourse which is at first at right angles to the face of the post, andthence, as soon as the cylindrical cutter (Z) has begun to act,

in a longitudinal course receding sufficiently from the face of the postto form a mortise which shall bind the dovetailed tenons of the rail asthey are pressed down in their sockets.

2. I claim, in combination with the aforesaid guides, the stops (1*)substantially as here arranged and appliedor the equivalents whereby thetable-is limited in its course to the particular range of cutting actionrequired for the time being.

In testimony whereof, I have hereunto set my hand before two subscribingwitnesses.

HENRY J. BETJEMANN.

Witnesses:

E. 'H. PUGH, EDWARD I-I. KNIGHT.

